1. Field of the Invention
The invention relates to an apparatus for processing chicken manure and more particularly to an apparatus for homogenizing and drying chicken manure to produce fertilizer and animal feed.
2. Technical Background
Animal waste is converted into compost by the process of fermentation. Composting of manure requires continuous circulation of air homogeneously through the manure with control of temperature and moisture content. If the manure is not mixed with air, ammonia can accumulate and produce increased protein breakdown. The process includes at least three operations: agitation of the manure, homogenization, and simultaneous aeration to provide oxygen for aerobic decomposition by micro organisms. The compost is then dried to a moisture content of no more than 45%.
In the conventional process for composing chicken manure, the general practice has been to store or pile the organic materials to be composted for a certain period and to periodically turn them over at a proper time interval to promote aerobic fermentation, a proper amount of air being preferably fed to the stored materials from the bottom thereof during the storage. Plowing or turning the piled materials over is indispensable in order to uniformly mix the materials as well as to fractionalize the materials so as to substantially increase the total area of the surface of the materials exposed to air. The material is dried in the sun or in a drum-type drier heated by means of oil burners. Belt type driers can also be used in place of a drum-type drier. Attempts have also been made to perform these operations by means of indirect driers, such as, for example, tube-type driers, but these resulted in operational malfunctions due to clogging.
Prior use of poultry manure as a fertilizer material has been somewhat restricted by low nitrogen content and the often accompanying malodor. Preparation of the raw manure invariably leads to unwanted decomposition and loss of nitrogen. Malodor is not surprising and something of a byproduct of the decomposition process. Other drawbacks to wider use of this material as a fertilizer are evident from an overview of the prior art.
Fermentation is an aerobic thermophilic reaction wherein heat is generated as the mixture decomposes and the temperature of the mixture progressively rises to an optimum value. The mixture remains at this elevated temperature while the decomposition process continues for a period of time, depending upon such variables as moisture content, manner and extent of aeration, and the nature of the mixture ingredients. Thereafter the mixture gradually cools and the production of aerobic bacteria ceases. The aerobic thermophilic reaction is maximized when all portions of the mass are slowly aerated uniformly and to the proper extent. In order to aerate the mixture properly it is necessary to agitate the whole mass slowly in such a manner that substantially all portions of the material are exposed to an optimum amount of air for an optimum period of time. If the mass is agitated too violently or if the amount of air is excessive, the mixture will be dried and cooled. On the other hand, if the air supplied is less than the optimum amount required or if the mass is not agitated properly the bacterial activity will not reach its maximum potential and the composting process will require an unduly long period of time.
Many devices are known which combine agitation, homogenization, and aeration. Agitation and homogenization have used a variety of means such as rotating milling mechanisms and augers, conveyors with agitators, horizontally reciprocating or linearly moving rakes or plows, and rotary drums with or without baffles or radial fingers projecting into the mixture. With such types of equipment the proper aeration has not been achieved because homogenization is not complete and uniform. For example, with rakes it is impractical, if not impossible, to agitate the mass so that the oxygen in the air will come into intimate contact with all portions of the material for the required time interval. In the case of rotary drums, some portions of the mass remain stagnant for an unduly long period of time while other portions are caused to fall or tumble rapidly through the air stream directed through the drum. In either case, substantially all portions of the mixture in the drum are not uniformly exposed to the air for the required period of time to achieve the optimum operating conditions to allow the reaction to progress at its maximum potential rate and to produce the maximum nutrient content.
Besides providing an excellent fertilizer, chicken manure can serve as a high grade food supplement comprising as much as 40% of the finished feed for chickens, having a protein value as high as 20% by weight. Chicken manure processed as feed can result in longer life of the animal as well as increased egg production. Chicken manure must be dried to about 10-17% moisture content and sterilized to be used as feed without composting. However, without complete composting or addition of unacceptable chemicals such as formaldehyde and urea, the final feed product will have an unacceptable odor.
At the present time there are no known chicken manure processing devices for practical commercial use which can produce compost or feed that is devoid of objectionable odor. This is because existing devices cannot adequately homogenize and aerate an entire mass of manure without expensive, complicated, and impractical devices.
The present invention processes chicken manure to produce animal feed and compost for fertilizer. The apparatus agitates, homogenizes, composts, and dries the manure to produce fertilizer, and agitates, homogenizes, and rapidly dries the manure to produce feed. Both the compost and feed have no objectionable odor. The apparatus uses a system of augers arranged vertically so that the manure is continuously raised, from the bottom of the processing bin to the top, from one end of the processing bin to the other end, and from one side of the processing bin to the other side. The augers thereby agitate and homogenize large quantities of manure, allowing air and heat from an air conditioning system to be distributed uniformly through the entire mass of manure. The thorough composting and/or the thorough drying create a fertilizer or feed that is devoid of objectionable odor.